Conventionally, in a technological field of electrical characteristic testing of a semiconductor integrated circuit, there is a known technology related to a conductive contact unit provided with a plurality of conductive contacts, each of which is arranged correspondingly to an external connecting terminal of the semiconductor integrated circuit. Such a conductive contact unit has a structure having a plurality of conductive contacts, a conductive contact holder having openings that accept the conductive contacts, and a test circuit that is electrically connected to the conductive contacts (for example, see Patent Document 1).
Generally, each of the conductive contacts included in the conductive contact unit is classified into: a signaling conductive contact that inputs and outputs an electrical signal to and from the semiconductor integrated circuit, that is, an test object; a grounding conductive contact that supplies a ground potential to the semiconductor integrated circuit; and a power-supplying conductive contact that supplies driving power to the semiconductor circuit. Each of the conductive contacts realizes the function thereof by being electrically connected to a signal generating circuit, for example, provided in the test circuit.
A holder substrate that contains the conductive contacts, is generally made of a conductive material, and has a potential equal to the ground potential. Because this holder substrate can cause a short circuit if the holder substrate is brought in contact with an electrode on the circuit substrate, or an electrode on the test object, it is necessary to provide an insulating layer. This insulating layer is often formed by coating.
On the contrary, on the inner circumference of an opening where the grounding conductive contact is inserted, a surface process, such as gold plating, is provided in some cases to improve electrical contact and prevent abrasion.
When the insulating layer is to be formed over the holder substrate, and the surface process is to be provided as described above, the insulating layer is at first formed by coating, the openings are formed thereon to accept these types of conductive contacts, and subsequently surface process, such as gold plating, is provided.
Patent Document 1: Japanese Patent Application Laid-open No. 2002-124552 (FIG. 1)